JP2002341272A - Deflecting scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the BD writing position of a multi-beam laser from being displaced. SOLUTION: A BD slit and a BD sensor are constituted as a single unit, and in the optical box, a BD detection unit is constituted rotatably and adjustably on the optical axis of a scanning lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection scanning apparatus using a multi-beam laser used for an image forming apparatus such as a laser beam printer and a laser facsimile.

[0002]

2. Description of the Related Art In recent years, the use of a plurality of light sources has been studied along with the high performance and high functionality of an image forming apparatus.
In particular, the use of multi-beam lasers having a plurality of laser emission points is increasing.

FIG. 5 shows a conventional deflection scanning apparatus. A light source unit S0 includes a multi-beam laser 101 having a plurality of laser emission points, and a plurality of laser beams emitted from the multi-beam laser 101. Laser beam L0, for example, in the case of two beams, two laser beams A and B are collimated by a collimator lens 101a, condensed into a linear light beam by a cylindrical lens 102, and incident on a reflection surface of a polygon mirror 103. I do.

The polygon mirror 103 is rotated at a high speed by the rotation of a motor 107 rotating at a high speed. The reflected light is deflected and scanned to form an image on a photosensitive drum on a rotating drum Do via an imaging lens 104.

A part of the laser light deflected by the polygon mirror 103 is reflected by the BD mirror 105, passes through the BD slit 106a, and passes through the condenser lens 106b
And enters the BD sensor 106c.

The plurality of laser beams incident on the BD sensor are converted from optical signals into electrical signals in a processing circuit, and are transmitted to the multi-beam laser 101 as scanning start signals. After receiving the scanning start signal, the multi-beam laser 101 starts writing modulation based on image information transmitted from the host computer.

[0007]

However, in the above conventional example using a multi-beam laser, the laser light emitted from a plurality of laser emission points may have a BD timing shift between the plurality of beams for various reasons. As a result, image defects occur due to a periodic writing position shift.

An object of the present invention is to provide a BD between a plurality of beams.
An object of the present invention is to provide a deflection scanning device using a multi-beam laser capable of eliminating timing deviation and enabling high-speed, high-quality printing.

For example, as shown in FIG. 8, when a horizontal line is created by two laser beams A and B, the left side is a normal image, and the right side is two beams, and the writing start position is periodic by ΔL mm. Shows a defective image when the writing position is shifted.

[0010]

In order to achieve the above object, a deflection scanning apparatus according to the present invention comprises a BD sensor for receiving a plurality of laser beams and a BD slit containing a BD slit for passing the beams to the BD sensor. The unit is integrally configured, and the BD detection unit is configured to be rotatable around the optical axis of the scanning lens in the optical box,
By rotating and adjusting the BD detection unit, the inclination angle of the BD slit changes and the timing at which each laser spot of a plurality of multi-beam laser beams enters the BD sensor changes. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 and 2 show an embodiment of the present invention, FIG. 1 is a main sectional view, and FIG. 2 is a top view thereof.

Since the configuration of the entire apparatus is the same as that of the conventional example, detailed description is omitted.

In the drawing, reference numeral 1 denotes a BD holder formed of a resin material, 1a denotes a BD slit formed at the tip thereof, 1b denotes a fitting portion for fitting the hole into the optical box 2, and 106b denotes a BD for condensing light. A lens 106c is a BD sensor, 2 is an optical box made of a resin material, and 2a is a fitting part for positioning and inserting a BD holder at a predetermined position.

In the above, a BD sensor 106c for receiving a plurality of laser beams and a BD detection unit 1 containing a BD slit 1a for passing the beams to the BD sensor are integrally formed, and the BD detection unit is provided in an optical box. 1 is configured to be rotatable around the optical axis center 0 of the scanning lens, and by adjusting the rotation of the BD detection unit 1, the inclination angle θ of the BD slit 1a changes as shown in FIG. The timing at which each of the plurality of multi-beam laser beams passes through the BD slit of the laser spot changes, and the timing at which the laser beam enters the BD sensor 106c changes.

After the rotation adjustment, the BD detection unit 1 is fixed to the optical box 2 with screws 10.

As a result, in the case of, for example, two laser beams A and B, the laser beam passing through the BD slit 1a is received by the BD sensor 106c and an electric signal having a rising waveform as shown in FIG. Is done.

In the figure, L is the slice level, and T is 2
This is the time interval between the two laser beams A and B when they are converted into electric signals by the BD sensor and output.

BD detection unit 1 fitted in optical box 2
Is adjusted around the optical axis center 0 of the scanning lens, the tilt angle θ of the BD slit 1a changes with respect to the multi-beam laser. For example, when the BD slit 1a is rotated clockwise, The time interval T is extended to T1.

As described above, by adjusting the rotation of the BD detection unit 1 attached to the fitting portion of the optical box 2, the BD writing timing between the multiple beams can be freely adjusted.

(Second Embodiment) FIG. 6 is a main sectional view showing a second embodiment of the present invention.

Since the configuration of the entire apparatus is the same as that of the first embodiment, a detailed description is omitted.

In the figure, reference numeral 21 denotes a BD holder formed of a resin material, and 21a denotes a fitting portion for fitting a BD slit 31 of a press member formed of a metal material formed of a separate member formed at the tip thereof. is there.

The shape of the BD slit, for example, its width dimension H
Is changed, only the BD slit 31 is replaced, so that all other components can be used in common.

[0024]

As described above, according to the present invention, the write timing between multiple beams can be freely adjusted by rotating and adjusting the BD detection unit 1 attached to the fitting portion of the optical box 2. . As a result, (1) by rotating and adjusting the BD detection unit,
The writing timing between the multi-beams can be easily changed, so that an expensive circuit and troublesome electric adjustment means are not required, and a low-cost apparatus can be provided.

(2) Since the BD slit and the BD sensor have the same rotation axis, as shown in FIG. 5, an area X passing through the BD slit 1a and receiving light by the BD sensor 106c is located near the center shown in the left diagram. Since the BD can be detected in a stable area of the sensor without being shifted from the ideal position to the end area X1 of the BD sensor 106c as shown in the right diagram, the reliability is high.

(3) Since the write timing between the multiple beams can be adjusted, the same BD detection unit can be used for other deflection devices and can be used in common.

As described above, a low-cost and highly reliable deflection scanning device can be realized, and the timing adjustment between multiple beams can be easily performed, so that a high-quality image can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view according to a first embodiment of the present invention.

FIG. 2 is a top view according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram according to the first embodiment of the present invention.

FIG. 6 is a sectional view according to a second embodiment of the present invention.

FIG. 7 is a top view showing a conventional example.

FIG. 8 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 BD holder 1a BD slit 1b Fitting part 2 Optical box 2a Fitting part 106b BD lens 106c BD sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 7/00 G02B 7/00 F K H04N 1/036 Z H04N 1/036 B41J 3/00 D 1/113 H04N 1/04 104A F-term (reference) 2C362 AA07 AA10 BA04 BA89 BB30 BB31 BB38 2H043 AB05 AB08 AB15 AB37 AE04 AE21 2H045 AA01 BA22 BA33 CA88 CA98 DA02 5C051 AA02 CA07 DA02 DB00 DB02 DB22 DB03 DB07 HA07 HA13 HA20 HB13 XA05

Claims (3)

[Claims] 1. A light source unit having a plurality of laser emission points, a deflection scanning means for deflecting a plurality of laser beams emitted from the light source unit by a polygon mirror and forming an image by a scanning lens, and writing the plurality of laser beams In a device in which synchronization detection means for controlling start synchronization by a horizontal synchronization signal is housed in an optical box, a BD sensor housing a BD sensor for receiving a plurality of laser beams and a BD slit for passing the laser beams to the BD sensor. A deflection scanning device, wherein a detection unit is integrally formed and an optical box is configured such that the BD detection unit can be rotated and adjusted around the optical axis of a scanning lens. 2. The deflection scanning device according to claim 1, wherein the rotation adjusting fitting portion is provided on a wall surface of the optical box so that the BD detection unit can be attached from outside the optical box. apparatus. 3. A BD between a BD sensor and a BD slit.
3. The deflection scanning device according to claim 1, wherein the deflection scanning device comprises a lens.